Pintle wires for clipper seams

ABSTRACT

A pintle wire unit consists of two side-by-side pintle wires, a lead-in wire arranged in end-to-end disposition relative to the said pintle wires, and a coupling member whereby the pintle wires and lead-in wire are joined together. The coupling member may comprise a open-ended sleeve with the opposed ends of which the pintle wires and lead-in wire are respectively engaged, and the wires may be secured to the coupling sleeve by means of an adhesive cement or by crimping the sleeve upon the wires. Alternatively, the wires may be joined together in the requisite end-to-end disposition by forming a moulded body on the wires in the region of intended join.

United States Patent PINTLE WIRES FOR CLIPPER SEAMS 11 Claims, 10 Drawing Figs. US. Cl 24/33, 14/207, 287/78, 16/168 Int. Cl Fl6g 3/02, A44b 19/00 Field of Search 24/205. 19,

33, 36, 207 (Cursory), 39 (Cursory); 287/78, 108, 109, 75 (curso y); 34/243 (curso y); 16/168; 74/231 (.loints),23l (Cursory; 198/193, 193 (curso y); 339/45 (M), 276 (T) Primary Examiner-Bernard A. Gelak Attorney-Roberts, Cushman & Grover ABSTRACT: A pintle wire unit consists of two side-by-side pintle wires, a lead-in wire arranged in end-to-end disposition relative to the said pintle wires, and a coupling member whereby the pintle wires and lead-in wire are joined together. The coupling member may comprise a open-ended sleeve with the opposed ends of which the pintle wires and lead-in wire are respectively engaged, and the wires may be secured to the coupling sleeve by means of an adhesive cement or by crimping the sleeve upon the wires. Alternatively, the wires may be joined together in the requisite end-to-end disposition by forming a moulded body on the wires in the region of intended 10m.

M n 15 he PATENTED APR27 19m SHEET 3 OF 4 HNTLE WlRES FOR CLlPlPER SEAMS This invention relates to flexible seams of the general type known as clipper seams, such seams now being commonly used for joining together the ends of dryer felts so that these assume the form of endless belts. Dryer felts of varying permeability, whether made from natural or synthetic materials, or mixtures thereof, are used on the drying sections of paper and board making machines, and may be of any width up to, say, 400 inches.

The well-known construction of clipper seam comprises a series of U-shaped wire clips, the hooked ends of which are clenched either in the extreme ends of the dryer felt or in the selvedge of narrow webbing attached thereto. When the ends of the untensioned dryer felt are fitted together with the U- shaped wire loops alternately interleaved, a pintle wire, of circular cross section and of suitable material, is threaded through the aligned wire loops, so fonning a hinged joint and enabling the dryer felt to run in the manner of an endless belt.

The single pintle wire used in the above-described form of clipper seam tended to suffer rapid wear and consequent early disintegration due to the sliding friction between the wire loops, or some of them, and the pintle wire (here serving as a hinge pin) when subjected to continuous reversing flexure such as occurs when the dryer felt is running on a high-speed paper machine. The wholly synthetic pintle wire described in our British Pat. No. 997,354, ha been found in practice to have a longer service life, other things being equal, than any other known construction of pintle wire.

Our British Pat. No. 1,1 14,602 describes an improved construction of clipper seam which has largely replaced the single pintle wire type of seam for the arduous duty of joining dryer felts. 1n the improved seam of Pat. No. 1,114,602 two pintle wires, each of circular transverse cross section, are provided through the interleaved sets of loops, the said wires, in use, being adapted to be maintained in rolling contact with each other under the tension in the felt, band, or the like. The wire loops of this improved seam are of similar form to those of a single pintle wire seam but are slightly longer, thus to accommodate the two pintle wires in side-byside disposition in the plane of the dryer felt and within the elongated space or tunnel enveloped by the interleaved wire loops. When the joint flexes under running tension, the twin pintle wire roll against each other and, as there is virtually no sliding friction between the pintle wires and the wire loops containing them, wear of the pintle wires is minimized and, consequently, this improved form of seam, known as the twin-wire clipper seam, is more reliable and has a longer service life than the single pintle wire type of seam.

While there twin-wire clipper seams have been shown to possess outstanding advantages when used for the purpose above described, extreme difficulty has hitherto been experienced in the manual operation of threading the two pintle wires through the tunnel formed by the aligned and interleaved wire loops whilst, at the same time, retaining the twin pintle wires in correct parallel alignment across the full width of the seam, that is to say, with the twin wires lying side by side in the plane of the dryer felt.

The object of the present invention, therefore, is to provide an improved composite unit by which the twin pintle wires may be speedily and simultaneously threaded through the wire loops of the seam and, at the same time, disposed therein in accurate alignment, 8 above described, thereby ensuring the best possible action a a flexible seam.

According to the invention, the two pintle wires lying side by side and a lead-in wire are placed end to end and are coupled together by any suitable means to form a strong and convenient composite unit.

in one form of the invention, the adjacent ends of the twin pintle wires and of the lead-in wire are clamped in their correct relative positions in a mould into which resinous or similar curable or settable material is introduced to form, after curing or setting, an effective coupling of the three wires, the mould being adapted to form a body having an external shape designed to facilitate its easy passage through the tunnel formed by the wire loops.

In another form of the invention, the leading ends of the two pintle wires are coupled to the trailing end of the lead-in wire by means of a tubular sheath formed of metal, or alternatively of plastic material. This sheath, which forms the coupling, is shaped externally to facilitate its easy passage through the wire loops, and is conveniently made about 2 to 3 inches in overall length. One end of the sheath is shaped to receive the twin pintle wires lying in mutual contact side by side, and the other end is shaped to receive the lead-in wire. These three wires are securely retained in the tubular sheath by any suitable adhesive cement, or in any other convenient manner.

The pintle wires are preferably, but not necessarily, of the all-synthetic construction described in our British Pat. No. 997,354, and their length exceeds by a reasonable margin the width of the dryer felt to which the seam is fitted.

The lead-in wire is preferably of rectangular cross section, and is fitted in the tubular sheath with its major axis in alignment with the twin pintle wires lying side by side. The lead-in wire is preferably made of hardened and tempered spring steel, so that it tends to straighten out when released from the coiled form in which it is packed for transport. The length of the lead-in wire is nonnally some 2 or 3 feet longer than the width of the dryer felt and its seam, and the leading end of the lead-in wire is suitably rounded off or pointed to enable it to pass smoothly through the tunnel formed by the wire loops.

When the wire clips are clenched in the selvedge of narrow webbing which is attached by sewing or other means to the ends of the dryer felt, the webbing is preferably of the tapered form described in our British Pat. No. 847,646.

The twin pintle wires and the lead-in wire, connected in the above-described manner, form a composite unit which is particularly convenient for use by the paper-machine staff when fitting a new dryer felt. The coil is first released from its temporary binding whereupon the lead-in wire straightens out by reason of its spring temper, and the twin pintle wires are straightened out by hand. The leading end of the lead-in wire is then inserted into the tunnel formed by the wire hooks, and is propelled by hand until the leading end emerges from the other side of the seam. During this operation, the loose ends of the dryer felt are preferably supported in such manner as to be capable of being readily drawn together as the lead-in wire is pushed through.

The emerging end of the lead-in wire is then preferably fitted with a suitable form of clamp to fonn a handle by which the lead-in wire is pulled through the seam loops as the twin pintle wires are simultaneously drawn into their correct position within the seam. At this stage, the lead-in wire and the tubular sheath coupling will have been passed right through the seam from the starting to the finishing side, and the pintle wires may now be severed and the coupling and lead-in wire discarded. The protruding ends of the twin pintle wires at each selvedge of the dryer felt may be knotted to prevent their moving endwise. Alternatively, the protruding ends may be laced into the fabric of the dryer felt or sewn thereto with equivalent effect.

Instead of allowing the coiled lead-in wire and coupled pintle wires to uncoil completely, as above described, prior to commencing to thread the former into the seam, the following alternative procedure is envisaged.

As supplied to the user, the twin pintle wires will be wound on to a drum of some 9 to 12 inches diameter, followed by the lead-in wire, which will be restrained, in any suitable manner, from unwinding until required. The drum may be enclosed in a cardboard box within which the drum is capable of rotating as the lead-in wire, followed by the coupled twin pintle wires, is manually drawn out of the box through a hole provided for that purpose.

Alternatively, the drum may be mounted on a temporary fulcrum, while the wires are unwound as they are threaded into the seam.

The invention will now be further described with reference to the accompanying drawings, of which:

H6. 1 is a longitudinal section of a dryer felt with the twinwire clipper seam fitted to tapered webbings sewn to the ends of the dryer felt;

FIG. 2 is a similar longitudinal section of a dryer felt with the twin-wire seam fitted directly to the ends of the dryer felt;

FIGS. 3 and 4 show in side elevation and plan, and by way of example only, one form of the composite unit comprising a lead-in wire, a tubular sheath coupling and twin pintle wires;

FIG. 5 is a cross section taken on line A-A of FIG. 4 and shows the shape of the tubular sheath at the twin pintle wire end;

FIG. 6 is a cross section taken on line 3-8 of FIG. 4 and shows the shape of the tubular sheath at the lead-in wire end;

FIGS. 7 to 9 inclusive show the progressive stages in threading the twin pintle wires simultaneously by means of the com posite unit shown in FIGS. 3 and 4; and

HG. 10 shows one manner in which the protruding ends of the twin pintle wires may be secured.

Referring now to FIG. 1, the ends of the 12, felt 10, 10, have attached to them, preferably by several parallel rows of machine sewing, the narrow webbing 13, 13 into the adjacent thicker selvedges of which the U-shaped wire clips 12, 12, are clenched by means of a suitable press. The webbing 13 is preferably of tapered cross section as shown in H6. 1, and as described in our British Pat. No. 847,646. The two rows of wire loops 12, 12 are interleaved and are then linked together by twin pintle wires ll, 11 for the purpose described in our British Pat. No. 1,114,602. The two ends of the dryer felt l0, 10, form a but joint at 9, which joint 9 is behind the centerline of the scam in the direction in which the dryer felt runs, as indicated by the arrow.

FlG. 2 shows a variation in which the webbings are dispensed with, and the wire clips 12, 12, are clenched directly in the ends of the dryer felt 10, 10, the extreme ends of which felt may be strengthened by doping them with resin, or similar stiffening agent. ln this particular case, it is preferred to provide a trailing flap 14, formed from thin synthetic fabric, to prevent the wire clips from marking the paper which, on a paper-making machine, is pressed by the dryer felt against the peripheries of a succession of steam-heated dryer cylinders. The trailing flap 14 is attached, by sewing, to the dryer felt ahead of the seam, the direction in which the dryer felt runs again being dictated by the arrow. Here again, the twin pintle wires ll, 11, are shown in their correct relative positions, that is to say, lying side by side in the plane of the dryer felt.

The composite unit, the subject of the present application is shown in FIGS. 3 to 6 inclusive, FIGS. 3 and 4 showing the unit in elevation and plan respectively. The tubular sheath coupling 15 consists, (in the embodiment illustrated), of a thin wall metallic tube with each half of its length separately swaged to a particular shape. Thus, at one end, as shown by FIG. 5, the shape or cross section is adapted to receive the twin pintle wires 11, 11, and at the other end, as shown by FIG. 6, to receive the lead-in wire 16, which wire 16 is rectangular in cross section and has its leading end suitably rounded or pointed.

As shown at 15c, the tubular sheath coupling assumes a smooth external profile well adapted to thread easily through the wire loops forming the clipper seam.

The twin pintle wires 11, 11, and the lead-in wire 16 are retained in the swaged tubular coupling 15 by any suitable adhesive cement (alternatively the tube may be crimped or indented in a press for this purpose).

FIGS. 7 to 9 inclusive illustrate the practical use of the composite unit as a convenient aid to the hitherto difficult operation of threading the twin pintle wires simultaneously into the clipper seam, and at the same time maintaining their correct side by side disposition. To facilitate this operation, the dryer felt is usually supported on the dryer cylinders and felt rolls of the paper machine with the felt-tensioning roll slacked back. The loose ends of the dryer felt are then preferably laid flat on a temporary platform, or plank, to which the ends of the felt are tacked with the two series of wire clips in approximate alignment.

As shown by FIG. 7, the rounded or pointed end of the leadin wire 16 is first inserted into one end of the seam and is then manually propelled through the tunnel formed by the wire loops until its leading end protrudes from the opposite end of the seam, as shown by FIG. 8. This operation is greatly facilitated by the lead-in wire being of rectangular cross section steel, appropriately hardened and tempered and with its leading end suitably rounded or pointed. Furthermore, the major axis, or width, of the rectangular section lead-in wire is only slightly larger than the overall diameter of a single pintle wire, consequently, the lead-in wire passes quite freely through the interleaved wire loops.

The protruding end of the lead-in wire 16, shown in FIG. 8, may be seized by a clamp or pliers to form a convenient grip or handle by which the lead-in wire 16, together with the coupling 15, may be pulled right through the seam, the twin pintle wires 11, 11 being simultaneously drawn into their correct final position in the seam, as shown by F lG. 9. This latter operation may be assisted by concurrent application of propelling force applied manually to the pintle wires adjacent to their entering end of the seam.

With the twin pintle wires thus duly threaded, the coupling 15 and the lead-in wire 16 may be cut away (as shown in FIG. 9) and discarded, after which the protruding ends of the twin pintle wires may be secured in any suitable manner as, for example, by bending them so as to lie parallel to the dryer felt selvedges to which they may be secured by hand whipping, as shown by FIG. 10.

The invention is not restricted to the exact features of the embodiment hereinbefore illustrated since alternatives will readily present themselves to one skilled in the art. Thus, for example, although in the specific embodiment disclosed the individual wires are secured in position by means of a suitable adhesive cement, it may be found convenient mechanically to secure the wires to the sheath. Furthermore, as has been indicated, instead of utilizing a tubular sheath with which the wires are engaged and to which such wires are secured, we may prefer to couple the wires together by embedding same in a resinous or similar material, the ends of the said wires being disposed within a mould and such mould being filled with a curable or settable material by means of which, upon curing or setting thereof, as appropriate, the wires are joined. The body defined by the cured or set material will be shaped to facilitate the passage thereof through the interleaved clips.

lclaim:

1. A pintle wire unit comprising two side by side pintle wires, a lead-in wire arranged in end-to-end disposition relative to said two pintle wires, and a rigid coupling element intermediate the pintie wires and the lead-in wire in which the ends of said pintle wires and lead-in wire are secured.

2. A pintle wire unit as claimed in claim 1 wherein the coupling element comprises a tubular sheath adapted to receive the pintle wires and the lead-in wire into engagement therewith at respective opposed ends thereof, the said sheath being adapted to maintain the said wires in engagement therewith.

3. A pintle wire unit as claimed in claim 2 wherein the sheath is shaped externally to facilitate the passage thereof through interleaved wire loops of a clipper seam.

4. A pintle wire unit as claimed in claim 1 wherein the leadin wire is of rectangular transverse cross section, the major dimension of such cross section being in a direction parallel to the plane defined by the axes of the pintle wires.

5. A pintle wire unit as claimed in claim 1 wherein the coupling means comprises an open-ended sheath of which one end is shaped to receive the side by side pintle wires and the other to receive the lead-in wire, the said sheath being adapted to maintain the said wires in engagement therewith.

6. A pintle wire unit as claimed in claim 5 wherein an adhesive cement is provided to secure the wires in position within the sheath.

7. A pintle wire unit as claimed in claim 5 wherein the sheath is of a crimpable material and is crimped onto the said wires thereby to secure such wires in position relative to the sheath.

8. A pintle wire unit comprising two side by side pintle wires, a lead-in wire arranged in end-to-end disposition relative to the said pintle wires, an open-ended coupling sleeve between the pintle wires and the lead-in wire, the pintle wires being engaged with one end of such coupling sleeve and the lead-in wire being engaged with the other end of such sleeve, the said sleeve being adapted to maintain the said wires in engagement therewith and having a shaped outer configuration thereto to facilitate the passage thereof through the interleaved loops of a clipper seam.

9. A pintle wire unit as claimed in claim 8 wherein that end 

1. A pintle wire unit comprising two side by side pintle wires, a lead-in wire arranged in end-to-end disposition relative to said two pintle wires, and a rigid coupling element intermediate the pintle wires and the lead-in wire in which the ends of said pintle wires and lead-in wire are secured.
 2. A pintle wire unit as claimed in claim 1 wherein the coupling element comprises a tubular sheath adapted to receive the pintle wires and the lead-in wire into engagement therewith at respective opposed ends thereof, the said sheath being adapted to maintain the said wires in engagement therewith.
 3. A pintle wire unit as claimed in claim 2 wherein the sheath is shaped externally to facilitate the passage thereof through interleaved wire loops of a clipper seam.
 4. A pintle wire unit as claimed in claim 1 wherein the lead-in wire is of rectangular transverse cross section, the major dimension of such cross section being in a direction parallel to the plane defined by the axes of the pintle wires.
 5. A pintle wire unit as claimed in claim 1 wherein the coupling means comprises an open-ended sheath of which one end is shaped to receive the side by side pintle wires and the other to receive the lead-in wire, the said sheath being adapted to maintain the said wires in engagement therewith.
 6. A pintle wire unit as claimed in claim 5 wherein an adhesive cement is provided to secure the wires in position within the sheath.
 7. A pintle wire unit as claimed in claim 5 wherein the sheath is of a crimpable material and is crimped onto the said wires thereby to secure such wires in position relative to the sheath.
 8. A pintle wire unit comprising two side by side pintle wires, a lead-in wire arranged in end-to-end disposition relative to the said pintle wires, an open-ended coupling sleeve between the pintle wires and the lead-in wire, the pintle wires being engaged with one end of such coupling sleeve and the lead-in wire being engaged with the other end of such sleeve, the said sleeve being adapted to maintain the said wires in engagement therewith and having a shaped outer configuration thereto to facilitate the passage thereof through the interleaved loops of a clipper seam.
 9. A pintle wire unit as claimed in claim 8 wherein that end of the coupling sleeve with which the lead-in wire is engaged is of rectangular cross section, the said lead-in wire having a like rectangular transverse cross section, and wherein that end of the sleeve with which the pintle wires are engaged is of oval cross section to receive the side by side wires into intimate engagement therewith.
 10. A pintle wire unit as claimed in claim 8 wherein the lead-in wire is of hardened and tempered spring steel.
 11. A pintle wire unit as claimed in claim 8 wherein the lead-in wire has a rounded forward extremity thereto. 